1. Technical Field
The invention relates to a process for conveying a raw coal in a pipeline and more particularly to a process for conveying a coarse raw coal as a slurry in a pipeline while simultaneously cleaning the coal.
2. Related Art
Coal can be conveyed in a slurry form through a pipeline from a mining site to a remote location. Coal slurrying requires substantial processing of the coal at the mine site including crushing, washing, and blending. Thereafter, the slurry is prepared and conveyed to the remote site via the pipeline. Additional processing is required at the pipeline outlet to separate the coal from the slurry vehicle before the coal can be applied to its end use.
U.S. Pat. No. 3,719,397 to Wasp discloses a process for conveying coal as a slurry via a pipeline to a remote site where the coal is recovered from the slurry. The slurry vehicle is then recycled to the pipeline inlet. The process requires washing and crushing the coal at the pipeline inlet which have attendant operating and equipment costs. Furthermore, the process requires large volumes of water which may not always be available at an arid location.
U.S. Pat. Nos. 4,178,233 and 4,265,737 to Smith et al use a fluorochlorocarbon to separate foreign material from coal. The fluorochlorocarbon is then employed as a slurry vehicle to convey the coal to a remote location where the coal is separated from the vehicle for its end use. The process requires considerable preparation of the coal before transport and high material costs for the vehicle.
A process is needed for conveying coal as a slurry via a pipeline which minimizes the necessary preparation of the coal at the pipeline inlet and in turn minimizes the equipment and vehicle costs. Further, a process is needed which delivers a slurry, containing a uniform coal readily separable from the slurry, to the remote pipeline outlet.